Bam! Pow! You hear these noises as you walk home late at night. You have a sudden urge to run away as quickly as you can. Where did this impulse originate? What led you to run and not stay? Why did your heart rate heighten, and now you are breathing quickly? Our fight-or-flight response and the role of adrenaline is the reason for these reactions!
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Jetzt kostenlos anmeldenBam! Pow! You hear these noises as you walk home late at night. You have a sudden urge to run away as quickly as you can. Where did this impulse originate? What led you to run and not stay? Why did your heart rate heighten, and now you are breathing quickly? Our fight-or-flight response and the role of adrenaline is the reason for these reactions!
When we detect a threatening stimulus such as a scream or a dog barking, the body sets off a complex chain reaction involving the endocrine and nervous systems.
The fight or flight response is activated by releasing hormones and activating the nervous system, preparing the body for action (typically through fight or flight, aka, running away).
What is the sequence of events and the stress hormones that cause fight-or-flight reactions?
Another way of understanding the responses of fight or flight is to think of the three stages that are involved. The three stages of fight-or-flight are:
The stress hormones adrenaline, noradrenaline, and cortisol are the messengers that trigger the physiological fight-or-flight response in the various organs, thanks to our endocrine system.
Adrenaline is one of the catecholamines produced in the adrenal glands. Adrenaline helps relax the smooth muscles of the lungs to aid in breathing. It is responsible for the rising heart rate, the constriction of peripheral blood vessels, and the constriction of skin cells, causing hair to stand up (causing goosebumps).
It also helps the liver break down glycogen to glucose and access sugar stores for immediate access to energy.
Cortisol is a stress hormone produced in reaction to chronic stress. Our bodies’ response to chronic stress is called the hypothalamic-pituitary-adrenal system (HPA axis). This system kicks in after the initial fight-or-flight response if stress is prolonged.
The sympathetic nervous system controls our flight or flight response. The sympathetic nervous system is activated like an alarm when there is perceived stress or danger. It’s a stress response that mobilises the body’s resources to deal with danger through our hormones and physical changes.
Once activated, it takes 20 minutes to an hour for the body to return to its normal state.
The fight-or-flight response, communicated via the sympathetic nervous system, affects many body parts. The body then prepares for the eventuality of either running away from the danger (flight) or fighting the danger (fight).
These effects help us in precarious situations where we must act and think quickly.
Your sympathetic nervous system activates our fight-or-flight reaction and affects our immune system. These effects are useful in repairing an injury quickly if we get hurt.
Many processes happen in both a sequence and in tandem when our fight-or-flight response is triggered.
For example, we can see opposite roles in our sympathetic and parasympathetic nervous systems. Well, they sound similar, so what makes them different?
Remember, our sympathetic nervous system is the bells and whistles that ring in alarm when there is a perceived danger. Our sympathetic nervous system is in control by activating our fight or flight response for as long as it is deemed necessary.
On the other hand, your parasympathetic nervous system sends signals when it’s okay to relax all those reactions and systems. When the parasympathetic nervous system is in control, our heart rate slows down along with our breathing rate. Other changes at this time are lower blood pressure and normal digestive rates.
To summarise, the sympathetic nervous system is involved in fight-or-flight, and the parasympathetic nervous system is involved in rest-and-digest.
Although it seems inconvenient to have a fight-or-flight reaction to public speaking or seeing a spider, a long time ago, when dangers were more apparent and life-threatening, a fight-or-flight response was (and still is) useful to the organism’s survival. Just imagine for a moment if someone were to have an underactive fight-or-flight response at the sight of a tiger or a fire. It would take them more time to perceive the danger, and their reaction would be slow and sluggish.
The seconds the body saves in being ready for action might mean the difference between life and death.
In this case, it was being able to dodge a tiger in time or run away from a fire.
Only our ancestors with these quick reactions survived long enough to pass on their genes.
Our life is full of events or happenings that could be perceived as stressful or fear-invoking. There is a multitude of examples that perhaps we have all collectively experienced.
An example of the fight-or-flight response in action can be seen if you are walking along a street during a dark night. In this scenario, you notice a rather scary figure following close behind you.
Your heart rate begins to climb, your palms grow a little sweaty, and your breathing quickens. The urge to run climbs, and as the figure gains on you, they break out into a run.
You run, too, muscles ready to go and full of energy, your heart beating fast to provide oxygenated blood to your limbs. More subtle changes less apparent can be seen in your gut.
In this example, we can see how the apparent danger presented by the strange figure produced a physiological response in your body. Heart rate increases to provide more blood to the limbs, your breathing rate increases to take in more oxygen to aid the increased blood supply, and other physiological changes occurred to prepare you for running away.
Sometimes, a fight or flight response may also occur in less appropriate situations.
You've been asked to give a speech at a huge conference. You find beforehand that your heart is beating fast, your palms are often sweaty, and you feel very stressed.
Before you walk onto the stage, your heart rate increases quite dramatically. The danger is less apparent in this scenario, but the fear-inducing scenario produces a similar response in your body. It goes to show how humans have developed, and more primitive responses have been carried into the modern world.
As discussed above, the stress hormones adrenaline, noradrenaline, and cortisol are the messengers that trigger the physiological fight-or-flight response in the various organs, thanks to the endocrine system. Adrenaline constricts blood vessels, increases blood flow to muscles by reducing intestine movements, and increases heart rate.
Adrenaline is thus important in the fight-or-flight response, allowing the body to prepare to move in cases of emergency.
Adrenaline is responsible for the immediate response to perceived danger by increasing the heart rate, respiratory rate, increasing blood flow to the brain and limbs as well as accessing energy stores via glucose within seconds. Cortisol acts similarly, but with a delayed reaction and it continues for longer.
The fight-or-flight response is a chain of physiological events in the body that happens in response to a stimulus that is perceived as dangerous. Your senses send a signal to the brain, which stimulates the sympathetic nervous system to tell your adrenal glands to produce hormones which in turn affect multiple organs throughout the body.
Adrenaline is the hormone best associated with the fight-or-flight response.
Stage fright is an example of the fight-or-flight response. Another example can be seen in running away from a dog if it snarls and moves to attack.
The first stage is alarm (fight or flight response), the second is resistance (body starts to recover) and the last is exhaustion (this is chronic stress). These are part of the theory of general adaption which describes the effects of chronic stress.
True or False: The fight-or-flight response is a chronic response that happens when an individual is faced with perceived danger.
False.
True or False: The fight-or-flight response is an acute stress response.
True.
True or False: To initiate the fight-or-flight response, there has to be a real danger.
True.
Which of the following is not an example of the fight-or-flight response?
Blushing when someone shouts at you.
True or False: ‘Flight’ refers to the act of removing yourself from danger.
True.
True or False: Freeze is another response the body can have to danger.
True.
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